1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a resistor with which high integration of the semiconductor device can be obtained and a method of manufacturing the same.
2. Description of the Related Art
In recent years, along with the progress in miniaturization and integration of a semiconductor device, various attempts have been made to form a number of semiconductor elements in a small area of a semiconductor chip. As the semiconductor device formed with those semiconductor elements, there is a semiconductor device provided with a ladder circuit which divides a voltage.
In the miniaturization and integration of the semiconductor device, it is extremely important to form the ladder circuit in a small area.
Conventionally, in order to miniaturize the ladder circuit, an insulating film is formed on a first resistor formed on a field region, a second resistor is formed on the insulating film to make the resistors into a two layer structure, and thus miniaturization and integration of the ladder circuit are attained. In a semiconductor device including such a ladder circuit, as shown in FIG. 2, in a field region of a semiconductor substrate 75, a first layer resistor 77 and a second layer resistor 66 are formed into a two layer structure via an interlayer insulating film 78 in a thickness direction of the semiconductor substrate 75 (for example, see JP 09-51072 A, JP 06-140573 A, and JP 2003-314296 A).
However, in the case of adopting the resistors having the two layer structure, there arise problems in that the manufacturing steps are complicated and the manufacturing cost increases, and also in that it is difficult to obtain specific accuracy equal to or more than specific accuracy of the ladder circuit formed of the resistors which are formed above the conventional field region. Conventionally, the resistors are formed only on the field region to be two-dimensionally arranged. Accordingly, when the resistors are formed in the semiconductor device, an area obtained by adding an area where the semiconductor element is formed and an area where the resistors are formed is necessary on the semiconductor substrate. Therefore, if the resistors can be three-dimensionally arranged, an area of the entire semiconductor device can be reduced, which leads to further progress in miniaturization and integration of the semiconductor chip.
Thus, a first object of the present invention is to provide a semiconductor device in which a breeder resistance circuit can be miniaturized and integrated. In addition, a second object of the present invention is to provide a method of manufacturing the semiconductor device which can be miniaturized and integrated.